vulkan/wsi: Fix lots of wayland format issues.
For shm/drm formats without alpha we add the vulkan format as only opaque, unless the vulkan format has no alpha channel. For shm/drm formats with alpha add the vulkan format with aplha.
Other fixed bugs: BGR8/RGB8 formats were overridden after the fallthrough, and they were totally missing in the shm format conversion function.
Edited by Georg Lehmann